(Letter No. 16) The Moslem calendar dates from Muhammad's emigration or Hijrah from Mecca to Medina in 622 A.D. The Moslem year begins with the month of Muharram of which the first ten days are observed by Shi'ah Moslems as part of their mourning period for the Imams. The tenth day is called Ashura and commemorates the martyrdom of Husayn, the grand-son of Muhammad, who was cut down by thirty-three strokes of swords and lances and decapitated: his clothes were torn from him and his naked body trampled by horses hooves.